The invention relates generally to maritime cable cutting under emergency conditions. In particular, the invention relates to a mechanism to expeditiously and reliably sever a heavy-duty cable used between ships for supply operations.
Naval ship replenishment at sea, also known as an undersea replenishment (UNREP) operation, involves rendezvous of approach and control ships on parallel courses, followed by connection of ships by a span cable. For liquid supplies, e.g., fuel, the delivering ship extends a hose along the cable to the receiving ship for connection to the appropriate receptacle. Other supplies, such as weapon stores can also be exchanged via cable suspension.
FIG. 1 shows an elevation view 100 of a conventional rigging configuration for UNREP between a delivering ship 110 and a receiving ship 120 for refueling operation. Structures and supports on the delivering ship include a wire topping pendant 125, a wire saddle whip 130, and an anti-toppling device 135. A span wire or cable 140 supports an inboard saddle 145, operating in conjunction with mezzanine and outboard saddles 150 and 155. The span wire 140 is typically 1⅜ inches (″) thick and comprises braided steel cable resistant to spontaneous breakage. The saddles 145, 150 and 155 elevate a supply hose 160 accompanied by a stress wire 165. After refueling completion a retrieving line returns the outboard saddle 155 to the delivering ship 110. A supply outlet 180 delivers fuel through the hose 160 supported by a receiving structure 190 on the delivery ship 120 and connected to its receiver inlet 195.
FIG. 2 shows an elevation view 200 of a conventional rigging configuration for weapons transfer between the delivering and receiving ships 110 and 120 to transfer a load 220 along a travel direction 225. The delivering ship 110 includes a ram tensioner 230, a high line winch 235, and out-haul winch 240, an in-haul winch 245 and a transfer head 250, which holds a tensioned highline 255, a tensioned in-haul line 260, and a tensioned out-haul line 265. The highline 255 and in-haul line 260 enable a trolley 270 to transfer the load 220. The delivering ship 110 also includes a kingpost 275 to elevate the transfer head 250. The receiving ship 120 includes a padeye 280 with an out-haul fairlead 285 to support the lines 255, 260 and 265.
In the event of an emergency replenishment termination, the cable is severed manually. This process is described in section 2.2.11 of “Underway Replenishment” especially pp. 2-11 through 2-15, issued as NWP 4-01.4 under the Chief of Naval Operations and available at http://www.hnsa.org/doc/pdf/unrepnwp04-01.pdf. FIG. 3 shows a perspective view 300 of the inboard ship 110 with its span wire 140. A manual cable cutter 310 is positioned on the span wire 140 by an assigned operator 320 to sever the cable when authorized during an emergency and abort the inter-ship delivery operations.